Now that's an Idea [Book]! Windows 8 App Store Idea Books (some with source too...)

Windows App Builder Blog - Idea books for commercial and enterprise app design—with sample code!

"...

While many of the idea books examine app scenarios and show great design patterns, a common question is, “Can you show me the code that you used to create that?” So, by popular demand, we’ve published several idea books with sample code so you can see the exact code used to create the sample app highlighted in the idea book. Here’s the current list of idea books that have an accompanying code example.

• Shopping apps – See how you can create a great shopping experience in your app. Sample code provided by Tallan Inc.
• Enterprise administration apps – See how businesses can use apps for enterprise administration. This idea book even has an app already in the Windows Store. Sample code provided by Citrix Systems Inc..
• Financial apps: SunGard – See how financial institutions can use apps for retirement portfolio planning. Sample code provided by Ratio Interactive.
• Medical apps: In-patient – See how hospitals can use apps to cater to patients during extended hospital stays. Sample code provided by Ratio Interactive.
• Medical apps: Manipal Hospital – See how medical professionals can use apps to plan their patient visits during medical rounds. Sample code provided by Ratio Interactive.
• Retail apps: Social CRM – See how retail managers can use apps to analyze market data, evaluate and monitor customer social activities, and provide direct engagement with customers to promote a positive brand image. Sample code provided by Ratio Interactive.

..."

Windows Dev Center - Windows Store apps - Enterprise Administration App

You don't have to invent the App Wheel, there's a ton of guidance, information, tips, tricks and even code for you to get started with...